Hard landing leads to gear failure

During an instructional flight in a Cessna 172RG over Redmond, Ore., the CFI and student were unable to fully extend or retract the left main landing gear. They made several attempts to fix the problem, but were unsuccessful, so they made a gear-up landing.

The post-accident examination revealed that the pivot assembly for the left main landing gear actuator had broken consistent with torsional fatigue.

The FAA previously issued an airworthiness directive which included an inspection of pivot assemblies for cracks, in accordance with a manufacturer’s service bulletin.

The AD called for repetitive inspections of the pivot assembly if the airplane experienced a hard landing, and the SB recommended, in small print, full recompliance after a hard landing. The SB was complied with 12 years and 2,730 flight hours before the accident.

During the investigation it was discovered that the airplane had been involved in a hard landing, and a re-inspection was conducted, however, re-compliance with the entire SB was not achieved as recommended, and the pivot failed 894 flight hours after the hard landing.

The NTSB attributed the accident to the failure of the left main landing gear pivot assembly during the landing.